Bluetooth: ath3k: don't use stack memory for DMA

Memory allocated by vmalloc (including stack) can not be used for DMA,
i.e. data pointer on usb_control_msg() should not point to stack memory.

Resolves:
https://bugzilla.redhat.com/show_bug.cgi?id=977558

Reported-and-tested-by: Andy Lawrence <dr.diesel@gmail.com>
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

drivers/bluetooth/ath3k.c

@@ -195,24 +195,44 @@ error:
 
 static int ath3k_get_state(struct usb_device *udev, unsigned char *state)
 {
-	int pipe = 0;
+	int ret, pipe = 0;
+	char *buf;
+
+	buf = kmalloc(sizeof(*buf), GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
 
 	pipe = usb_rcvctrlpipe(udev, 0);
-	return usb_control_msg(udev, pipe, ATH3K_GETSTATE,
+	ret = usb_control_msg(udev, pipe, ATH3K_GETSTATE,
 			      USB_TYPE_VENDOR | USB_DIR_IN, 0, 0,
-			state, 0x01, USB_CTRL_SET_TIMEOUT);
+			      buf, sizeof(*buf), USB_CTRL_SET_TIMEOUT);
+
+	*state = *buf;
+	kfree(buf);
+
+	return ret;
 }
 
 static int ath3k_get_version(struct usb_device *udev,
 			struct ath3k_version *version)
 {
-	int pipe = 0;
+	int ret, pipe = 0;
+	struct ath3k_version *buf;
+	const int size = sizeof(*buf);
+
+	buf = kmalloc(size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
 
 	pipe = usb_rcvctrlpipe(udev, 0);
-	return usb_control_msg(udev, pipe, ATH3K_GETVERSION,
+	ret = usb_control_msg(udev, pipe, ATH3K_GETVERSION,
-			USB_TYPE_VENDOR | USB_DIR_IN, 0, 0, version,
+			      USB_TYPE_VENDOR | USB_DIR_IN, 0, 0,
-			sizeof(struct ath3k_version),
+			      buf, size, USB_CTRL_SET_TIMEOUT);
-			USB_CTRL_SET_TIMEOUT);
+
+	memcpy(version, buf, size);
+	kfree(buf);
+
+	return ret;
 }
 
 static int ath3k_load_fwfile(struct usb_device *udev,